Highlights

A battery backup would add Rs. 25,000 to this cost but is not recommended unless absolutely necessary due to losses when charging or drawing power

Any further decrease in PV module prices are not likely to significantly reduce project cost as modules comprise only half the total cost of the project

Customers should check that the PV plant capacity quoted by vendor is for the module capacity and not the inverter capacity

The cost of a rooftop solar PV system depends on the function it serves (to feed power into the grid, to support the load during a power failure, etc.) and incentives/subsidies available. It should be noted that all solar PV systems function by matching the voltage from some other source. Therefore the system has to be integrated with the grid, a battery backup, or a diesel generator.

Types of rooftop solar PV systems

Rooftop solar PV systems are of 3 types:

Grid-tied – These rooftop systems are primarily designed to supply the generated power to the grid and also power the load. These systems will NOT generate power during a power failure as the inverter shuts down the system to stop sending power into the grid and avoids the risk of electrocuting utility personnel who are working to repair the grid

Grid-interactive – This system works in conjunction with either a battery backup or diesel generator to support the load even during a power failure.

Off-grid – This system does not work with the grid and is designed to work only with a battery backup or diesel generator in off-grid applications

The difference between the systems lies in the kind of inverter used, and the inclusion of batteries. As